The relationship between personal characteristics (ability/personality) of late mid-career professionals and aspects of knowledge obsolescence and obsolescence-resistant behaviors will be examined in three pilot studies. Tenured mid-career university faculty members representing two groups of disciplines--those involved in high (engineering, chemistry) vs low (English, basic math) susceptibility to technological change--will be interviewed regarding selected aspects of knowledge obsolescence in their disciplines and those updating behaviors employed to counteract obsolescence. Two interview-derived behavior scales will be developed for each of the four disciplines, assessing knowledge Obsolescence and Updating Activities. These measures will then be employed as criterion variables to examine the role of cognitive abilities and personality factors as possible predictors of individual differences in obsolescence and obsolescence-resistant behaviors. The resulting measures and knowledge base are the necessary first step to design a more extensive research program on personal characteristics related to professional obsolescence. Such research findings will be useful in design of infividual coulseling and intervention programs for late mid-career professionals.